甲基乙烯醚和OH反应机理的理论研究

Theoretical studies on mechanisms of OH reaction with methyl vinyl ether

利用量子化学从头计算的方法对甲基乙烯醚的两个异构体之间的转化，羟基与顺式-甲基乙烯醚和反式-甲基乙烯醚的加成反应，以及羟基提取甲基上的氢原子的反应机理进行了研究。研究结果表明：顺式-甲基乙烯醚比反式-甲基乙烯醚更加稳定，在QCISD/6-31G（d,p）//BHandHLYP/6-311＋＋G（d,p）理论水平下，OH加到顺式-甲基乙烯醚1号位的碳原子上需要跨越的能垒比其它反应通道需要跨越的能垒少7.5-34KJ/mol，因此是主要的反应通道，而OH加在反式-甲基乙烯醚2号位的碳原子上所需要跨越的能垒比其它反应路径所需要跨越的能垒少8.3-26.7kJ/mol，因此是主要的反应路径。利用经典过渡态理论计算了总的速率常数。

The interconversion of the two distinct isomers of methyl vinyl ether （MVE） -called synperiplanar and antiperiplanar, the reaction mechanisms of OH-MVE adducts and H-atom abstraction of methyl group were studies ab initio methods at the BHandHLYP/6-311＋＋G（d,p） level of theory for optimized geometries and frequency calculations and at the QCISD/6-31G（d,p） level for the single point energy calculations. The calculated results show that the synperiplanar MVE is more 7.1kJ/mol stable than antiperiplanar MVE at the QCISD/6-31G（d,p）// BHandHLYP/6-311＋＋G（d,p） level of theory, which is in good agreement with the experimental value. At he same level of theory mentioned above, the Hydroxyl radical, OH, addition to C1 of the C=C double bond in the synperiplanar MVE need less 7.5-34KJ/mol energy than the other pathways for OH attack. However, the activated energy of OH addition to C2 of the C=C double bond in the antiperiplanar MVE is less 8.3-26.7kJ/mol than the other channels for OH attack. The overall rate constant is calculated using the canonical transition state theory.